Mitochondrial and alpha-proteobacterial time of divergence - a question of antecedence
(English)Manuscript (Other academic)
Mitochondria are believed to have originated by the incorporation of an alpha-proteobacterium into an un-defined "proto-eukaryote", although the exact nature of the two participants in this endo-symbiotic event is not known. Attempts to place the endo-symbiont with a specific group of extant alpha-proteobacteria has in most cases identified the Rickettsiales as the sister-group to mitochondria, although recent work has shown that this could be due to methodological artefacts and that the mitochondria should instead be considered a sister-clade to alphaproteobacteria. Equally uncertain is the time at which this endo-symbiotic event took place, and if it coincides with the event that gave rise to the eukaryotes themselves. In this work we attempt to use molecular dating methods to compare the time-point of mitochondrial divergence to the time-point of divergence of the alpha-proteobacteria, under the two hypothetical topologies mentioned. We show that if mitochondria are considered as a sister-clade to the alpha-proteobacteria, mitochondria likely diverged prior to the radiation of extant alpha-proteobacteria, and that the alpha-proteobacterial clade itself might be significantly younger than shown in previous analyses.
Biochemistry and Molecular Biology
Research subject Molecular Biology
IdentifiersURN: urn:nbn:se:uu:diva-100845OAI: oai:DiVA.org:uu-100845DiVA: diva2:211106